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Types, Properties and Grades of Asphalt-Part B

Types, Properties and Grades of Asphalt-Part B. PG Specifications. Fundamental properties related to pavement performance Environmental factors In-service & construction temperatures Short and long term aging. Superpave Asphalt Binder Specification. The grading system is based on Climate.

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Types, Properties and Grades of Asphalt-Part B

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  1. Types, Properties and Grades of Asphalt-Part B

  2. PG Specifications • Fundamental properties related to pavement performance • Environmental factors • In-service & construction temperatures • Short and long term aging

  3. Superpave Asphalt Binder Specification The grading system is based on Climate PG 64 - 22 Min pavement temperature Performance Grade Average 7-day max pavement temperature

  4. SHRP A-648A Temperatures > 20 years • Superpave Weather Database • 6500 stations in U.S. and Canada • Annual air temperatures • hottest seven-day temp (avg and std dev) • coldest temp (avg and std dev) • Calculated pavement temps used in PG selection: • High temperature • 20 mm below the surface of mixture • Low temperature • at surface of mixture Pave temp = f (air temp, depth, latitude)

  5. PAV Long Term Aging RTFO Short Term Aging No aging Superpave Tests Low Temp Cracking Rutting Fatigue Cracking Construction [DTT] [RV] [BBR] [DSR]

  6. Tests Used in PG Specifications Construction BBR DSR RV

  7. Concentric Cylinder Rheometers • Concentric Cylinder

  8. Rotational Viscometer (Brookfield) Torque Motor Inner Cylinder Thermosel Environmental Chamber Digital Temperature Controller

  9. Mixing/Compaction Temps Viscosity, Pa s 10 5 1 .5 Compaction Range .3 .2 Mixing Range .1 100 110 120 130 140 150 160 170 180 190 200 Temperature, C

  10. Original Properties, Rutting, and Fatigue DSR BBR RV

  11. DSR Equipment Computer Control and Data Acquisition DSR Equipment

  12. Motor Parallel Plates with Sample Area for Liquid Bath

  13. 25 mm Plate with Sample

  14. Dynamic Shear Rheometer (DSR) • Parallel Plate

  15. Oscillating Plate B C A Fixed Plate B Test operates at 10 rad/sec or 1.59 Hz 360o = 2 p radiansper circle 1 rad = 57.3o Time A A C 1 cycle

  16. Elastic Viscous B Strain Time A A C Strain out-of-phase d = 90o Strain in-phase d = 0o

  17. Complex Modulus, G* Viscous Modulus, G” d Storage Modulus, G’ Complex Modulus is the vector sum of the storage and viscous modulus

  18. Short Term Binder Aging0 • Rolling Thin Film Oven • Simulates aging from hot mixing and construction

  19. Inside of RTFO Fan Rotating Bottle Carriage Air Line

  20. Permanent Deformation Addressed by: G*/sin d on unaged binder > 1.00 kPa G*/sin d on RTFO aged binder > 2.20 kPa For the early part of the service life

  21. Permanent Deformation Question: Why a minimum G*/sin d to address rutting Answer: We want a stiff, elastic binder to contribute to mix rutting resistance How: By increasing G* or decreasing d

  22. Fatigue BBR RV DSR

  23. Fatigue Cracking Function of repeated traffic loads over time (in wheel paths)

  24. Testing • Aged binder • Since long term performance problem, include: • Short term aging • Long term aging • Determine DSR parameters using 8 mm plate and intermediate test temperature

  25. Pressure Aging Vessel(Long Term Aging) • Simulates aging of an asphalt binder for 7 to 10 years • 50 gram sample is aged for 20 hours • Pressure of 2,070 kPa (300 psi) • At 90, 100 or 110 C

  26. Pressure Aging Vessel Rack of individual pans (50g of asphalt / pan) Bottom of pressure aging vessel Vessel Lid Components

  27. Pressure Aging Vessel Courtesy of FHWA

  28. Fatigue Cracking • G* (sin d) on RTFO and PAV aged binder • The parameter addresses the later part of the fatigue life • Value must be < 5000 kPa

  29. Fatigue Cracking • Question: Why amaximumG* sin d to address fatigue? Answer: We want a soft elastic binder (to sustain many loads without cracking) How: By decreasing G* or decreasing d

  30. Thermal Cracking BBR RV DSR

  31. Bending Beam Rheometer Computer Deflection Transducer Air Bearing Load Cell Fluid Bath

  32. Bending Beam Rheometer Sample

  33. Bending Beam Rheometer Equipment Fluid Bath Loading Ram Cooling System

  34. Bending Beam Rheometer • S(t) = P L3 4 b h3d (t) Where: S(t) = creep stiffness (M Pa) at time, t P = applied constant load, N L = distance between beam supports (102 mm) b = beam width, 12.5 mm h = beam thickness, 6.25 mm d(t) = deflection (mm) at time, t

  35. Bending Beam Rheometer • Evaluates low temperature stiffness properties • Creep stiffness • Slope of response (called m-value) Log Creep Stiffness, S(t) 8 15 30 60 120 240 Log Loading Time, t (sec)

  36. Is Stiffness Enough? • No. Need to assess strain needed to break specimen. • Thermal cracking occurs when strain is too great • Direct tension test • Currently (1998) in specification • New equipment is now available

  37. Direct Tension Test Load Stress = s = P / A D L sf D Le ef Strain

  38. Direct Tension Test Courtesy of FHWA

  39. Direct Tension Test Courtesy of FHWA

  40. PAV Long Term Aging RTFO Short Term Aging No aging Summary Low Temp Cracking Fatigue Cracking Rutting Construction [DTT] [RV] [DSR] [BBR]

  41. Performance Grades CEC Avg 7-day Max, oC PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82 1-day Min, oC -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 ORIGINAL > 230 oC (Flash Point) FP <3Pa.s@135 oC (Rotational Viscosity) RV (Dynamic Shear Rheometer) DSR G*/sin  > 1.00 kPa 46 52 58 64 70 76 82 (ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 % (Dynamic Shear Rheometer) DSR G*/sin  > 2.20 kPa 46 52 58 64 70 76 82 (PRESSURE AGING VESSEL) PAV 20 Hours, 2.07 MPa 90 90 100 100 100 (110) 100 (110) 110 (110) (Dynamic Shear Rheometer) DSR G* sin  < 5000 kPa 28 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31 ( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value S < 300 MPa m > 0.300 -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Report Value (Bending Beam Rheometer) BBR Physical Hardening > 1.00 % (Direct Tension) DT -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

  42. How the PG Spec Works 58 64 CEC Spec Requirement Remains Constant Avg 7-day Max, oC PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82 1-day Min, oC -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 ORIGINAL > 230 oC (Flash Point) FP <3Pa.s@135 oC (Rotational Viscosity) RV (Dynamic Shear Rheometer) DSR G*/sin  > 1.00 kPa 46 52 58 64 70 76 82 (ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 % (Dynamic Shear Rheometer) DSR G*/sin  > 2.20 kPa 46 52 58 64 70 76 82 (PRESSURE AGING VESSEL) PAV 20 Hours, 2.07 MPa 90 90 100 100 100 (110) 100 (110) 110 (110) Test Temperature Changes (Dynamic Shear Rheometer) DSR G* sin  < 5000 kPa 28 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31 ( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value S < 300 MPa m > 0.300 -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Report Value (Bending Beam Rheometer) BBR Physical Hardening > 1.00 % (Direct Tension) DT -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

  43. Permanent Deformation CEC Avg 7-day Max, oC PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82 1-day Min, oC -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 ORIGINAL > 230 oC (Flash Point) FP <3Pa.s@135 oC (Rotational Viscosity) RV (Dynamic Shear Rheometer) DSR G*/sin  > 1.00 kPa 46 52 58 64 70 76 82 (ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 % • Unaged • RTFO Aged (Dynamic Shear Rheometer) DSR G*/sin  > 2.20 kPa 46 52 58 64 70 76 82 (PRESSURE AGING VESSEL) PAV 20 Hours, 2.07 MPa 90 90 100 100 100 (110) 100 (110) 110 (110) (Dynamic Shear Rheometer) DSR G* sin  < 5000 kPa 28 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31 ( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value S < 300 MPa m > 0.300 -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Report Value (Bending Beam Rheometer) BBR Physical Hardening > 1.00 % (Direct Tension) DT -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

  44. Fatigue Cracking CEC Avg 7-day Max, oC PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82 1-day Min, oC -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 ORIGINAL > 230 oC (Flash Point) FP <3Pa.s@135 oC (Rotational Viscosity) RV (Dynamic Shear Rheometer) DSR G*/sin  > 1.00 kPa 46 52 58 64 70 76 82 (ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 % (Dynamic Shear Rheometer) DSR G*/sin  > 2.20 kPa 46 52 58 64 70 76 82 (PRESSURE AGING VESSEL) PAV 20 Hours, 2.07 MPa 90 90 100 100 100 (110) 100 (110) 110 (110) (Dynamic Shear Rheometer) DSR G* sin  < 5000 kPa 28 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31 PAV Aged ( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value S < 300 MPa m > 0.300 -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Report Value (Bending Beam Rheometer) BBR Physical Hardening > 1.00 % (Direct Tension) DT -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

  45. Low Temperature Cracking CEC Avg 7-day Max, oC PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82 1-day Min, oC -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 ORIGINAL > 230 oC (Flash Point) FP <3Pa.s@135 oC (Rotational Viscosity) RV (Dynamic Shear Rheometer) DSR G*/sin  > 1.00 kPa 46 52 58 64 70 76 82 (ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 % (Dynamic Shear Rheometer) DSR G*/sin  > 2.20 kPa 46 52 58 64 70 76 82 (PRESSURE AGING VESSEL) PAV 20 Hours, 2.07 MPa 90 90 100 100 100 (110) 100 (110) 110 (110) (Dynamic Shear Rheometer) DSR G* sin  < 5000 kPa 28 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31 ( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value S < 300 MPa m > 0.300 PAV Aged -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Report Value (Bending Beam Rheometer) BBR Physical Hardening > 1.00 % (Direct Tension) DT -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

  46. Low Temperature Cracking CEC Avg 7-day Max, oC PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82 1-day Min, oC -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 ORIGINAL > 230 oC (Flash Point) FP <3Pa.s@135 oC (Rotational Viscosity) RV (Dynamic Shear Rheometer) DSR G*/sin  > 1.00 kPa 46 52 58 64 70 76 82 (ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 % (Dynamic Shear Rheometer) DSR G*/sin  > 2.20 kPa 46 52 58 64 70 76 82 (PRESSURE AGING VESSEL) PAV 20 Hours, 2.07 MPa 90 90 100 100 100 (110) 100 (110) 110 (110) (Dynamic Shear Rheometer) DSR G* sin  < 5000 kPa 28 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31 ( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value S < 300 MPa m > 0.300 PAV Aged -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Report Value (Bending Beam Rheometer) BBR Physical Hardening > 1.00 % (Direct Tension) DT -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

  47. Miscellaneous Spec Requirements CEC Avg 7-day Max, oC PG 46 PG 52 PG 58 PG 64 PG 70 PG 76 PG 82 1-day Min, oC -34 -40 -46 -10 -16 -22 -28 -34 -40 -46 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -40 -10 -16 -22 -28 -34 -10 -16 -22 -28 -34 ORIGINAL > 230 oC FlashPoint (Flash Point) FP <3Pa.s@135 oC (Rotational Viscosity) RV (Dynamic Shear Rheometer) DSR G*/sin  > 1.00 kPa 46 52 58 64 70 76 82 MassLoss (ROLLING THIN FILM OVEN) RTFO Mass Loss < 1.00 % (Dynamic Shear Rheometer) DSR G*/sin  > 2.20 kPa 46 52 58 64 70 76 82 (PRESSURE AGING VESSEL) PAV 20 Hours, 2.07 MPa 90 90 100 100 100 (110) 100 (110) 110 (110) (Dynamic Shear Rheometer) DSR G* sin  < 5000 kPa 28 10 7 4 25 22 19 16 13 10 7 25 22 19 16 13 31 28 25 22 19 16 34 31 28 25 22 19 37 34 31 28 25 40 37 34 31 ( Bending Beam Rheometer) BBR “S” Stiffness & “m”- value S < 300 MPa m > 0.300 -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24 Report Value (Bending Beam Rheometer) BBR Physical Hardening > 1.00 % (Direct Tension) DT -24 -30 -36 0 -6 -12 -18 -24 -30 -36 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 -30 0 -6 -12 -18 -24 0 -6 -12 -18 -24

  48. Summary of How to Use PG Specification • Determine • 7-day max pavement temperatures • 1-day minimum pavement temperature • Use specification tables to select test temperatures • Determine asphalt cement properties and compare to specification limits

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